Structural engineering dominated geotechnical structured permanent supporting system and design method

ABSTRACT

The present disclosure provides a structural engineering dominated geotechnical structured permanent supporting system and a design method, and belongs to the technical field of underground structures. Through the technical solutions, the structural engineering dominated geotechnical structured permanent supporting system comprises a supporting structure designed on the basis of the partial coefficient of a permanent load, the supporting structure is connected to frame columns of a main structure through a plurality of connecting members arranged at intervals, and a partition wall for blocking soil mass is arranged between every two adjacent frame columns to form a permanent supporting system only bearing soil pressure in the horizontal direction of the supporting structure. When the system is designed, the combined action generated after the main structure and the supporting structure are connected is considered, so that the use of materials is reduced, and the cost is reduced.

TECHNICAL FIELD

The present disclosure relates to the technical field of underground structures and, and particularly relates to a structural engineering dominated geotechnical structured permanent supporting system and a design method.

BACKGROUND ART

At present, foundation pit supporting design belongs to geotechnical engineering major, and underground structure design belongs to structural engineering design. The foundation pit supporting structure serves the underground structure construction as the goal, and provides a safe and stable space for the underground structure construction. Therefore, the foundation pit supporting structure and the main underground structure are inseparable in the same site. At present, due to the separation of the two majors, the foundation pit supporting structure appears as a temporary measure, and a lot of materials are wasted, resulting in environmental pollution.

The existing underground structure system has the following problems.

Firstly, in the design process, structural engineers design the main structure, and geotechnical engineers design the supporting structure, so that the separation of the main structure and supporting structure in the design results in repeated structures in the functions of the structures of the two parts. During the construction of the underground structure, the soil pressure is borne by the support. After the construction of the underground structure is completed, the supporting structure is out of action after backfilling of the groove, and the basement exterior wall in the main structure bears the same soil pressure. However, the supporting structure is not recycled. The research shows that the supporting structure remaining in the underground still plays a role, ignoring the role of support is that structural engineers do not consider the subjective acts of the supporting structure, so the basement exterior wall at least partially repeats the permanent function of the supporting structure.

In such a project, the same load-soil pressure in geotechnical and structural professional design tasks is borne by the two structures, so that the waste is inevitable and obviously unreasonable.

Secondly, at present, in the related structural system considering the combined action of the supporting structure and the main structure, there are some cases of using some connecting members to transform supporting piles and walls into permanent support, but that is a method of active connection of geotechnical engineering with structural engineering, which is actually passive and a good hope. The method can be called “structural geotechnicalization”. When the supporting structure of foundation pit is designed in the geotechnical engineering major, main underground structural members are used so that structural members play the function of geotechnical engineering in the excavation stage. In fact, the method can save the cost and reduce the environmental pollution. However, due to the increased workload of structural engineering, structural engineering is not very positive, cooperative or active, and there are few successful cases.

Therefore, the situation of waste is more and more serious in the development of foundation pit engineering for several decades. Now it is urgent to change the temporary man-made waste of foundation pit engineering by taking high-quality development and implementing low-carbon strategy.

SUMMARY

In view of disadvantages in the prior art, the purpose of the present disclosure to provide a structural engineering dominated geotechnical structured permanent supporting system and a design method. According to the method, at the beginning of the design, the main action of the structural engineering major is to confirm that members such as supporting piles and underground continuous walls in the supporting structure designed in the geotechnical engineering major, as parts of the main structure, are permanently used and always bear soil pressure. It is confirmed that a basement exterior wall designed in the structural engineering major does not bear soil pressure any longer, and can only bear side pressure of backfilled soil in grooves. Structural supports and connecting beams in the structural engineering major are connected with supporting structures to connect the supporting piles and walls and the underground structure together. Therefore, only the supporting piles and walls bear the soil pressure. The structural arrangement of the basement exterior wall can no longer bear the soil pressure, and the thickness of the exterior wall is reduced (the exterior wall can also be omitted under appropriate conditions), so that the use of materials is reduced, the cost is reduced, and the pollution is reduced. The method is also called a geotechnical structuring design method, namely, under the main action of the structural engineering major, the foundation pit supporting structure designed in the geotechnical engineering major becomes a constituent part of the main structure.

In order to achieve the above-mentioned purpose, the present disclosure is realized through the following technical scheme.

In the first aspect, the embodiment of the present disclosure provides a structural engineering dominated geotechnical structured permanent supporting system, comprising a supporting structure designed on the basis of the partial coefficient of a permanent load, wherein the supporting structure is connected to frame columns of a main structure through a plurality of connecting members arranged at intervals, and a partition wall for blocking soil mass is arranged between every two adjacent frame columns to form a permanent supporting system only bearing soil pressure in the horizontal direction of the supporting structure.

As further implementation type, backfilled soil is filled between the partition wall and the supporting structure.

As further implementation type, the material strength of the supporting structure is the same as or higher than that of the main structure.

As further implementation type, the backfilled soil is rammed backfilled soil, and the side, away from the backfilled soil, of the supporting structure is natural soil.

In the second aspect, the embodiment of the present disclosure further provides a design method of the structural engineering dominated geotechnical structured permanent supporting system, comprising the following steps:

designing the supporting structure according to the partial coefficient of the permanent load in advance; designing the main structure without a basement exterior wall, and designing the connecting members;

constructing the supporting structure, excavating the soil mass inside a foundation pit and treating a substrate;

constructing the main structure, and connecting the main structure with the supporting structure through the connecting members; and

constructing the partition walls in grooves, and then backfilling soil mass in the grooves.

As further implementation type, when the supporting structure is designed, considering the influence of the combined action of the main structure and the supporting structure in later period, the main structure can bear the soil pressure permanently.

As further implementation type, based on the design of the main structure, the supporting structure is designed in cooperation with the main structure.

As further implementation type, the inner side of the supporting structure, the outer side of the partition wall and the connecting member are all subjected to waterproof and antiseptic treatment.

As further implementation type, after the soil mass in the grooves is backfilled, the backfilled soil is compacted in layers.

As further implementation type, the supporting members of the supporting structure are supporting piles or underground continuous walls.

The present disclosure has the following beneficial effects:

Firstly, in the present disclosure, the structural engineering is dominated, and in cooperation with the geotechnical engineering, considering the influence of the combined action of the main structure and the supporting structure in later period at the beginning of the design, the supporting structure is designed according to the partial coefficient of the permanent load, and the original temporary support is promoted to be the supporting structure with a permanent function; the basement exterior wall is omitted, and the partition wall is taken as a substitute to combine the functions of the common supporting structure and the basement exterior wall into one; and the purpose of combining the supporting structure and the functionally repeated or similar members in the main structure is achieved, so that the use of materials is reduced, the cost is reduced, and the pollution to the underground space is reduced.

Secondly, the partition wall is arranged at the position of the original basement exterior wall, the partition wall only blocks backfilled soil and bears the soil pressure; the main structure is connected to the supporting structure through the connecting members, and the backfilled soil is tamped in layers; the backfilled soil generates a horizontal force on the supporting structures on the two sides and the main structure, so that the embedding and fixing actions of the soil on the underground structure are achieved; at the moment, the supporting structure, the connecting members and the main structure form a complete joint action, and the backfilled soil, the supporting structure and the main structure form a whole body; the horizontal force of external soil on the whole structure is firstly applied to the supporting structure, and then the supporting structure is transmitted to the main structure through the connecting members and the backfilled soil, so that the whole underground structure system achieves a combined action.

BRIEF DESCRIPTION OF THE DRAWINGS

Attached figures of the description which form a part of the present disclosure are used for providing further understanding of the present disclosure, and the illustrative embodiments and description thereof in the present disclosure are used for explaining the present disclosure and are not to be construed as an undue limitation of the present disclosure.

FIG. 1 is a design block diagram of an existing underground structure;

FIG. 2(a) is a schematic diagram of an existing supporting pile as a main supporting member;

FIG. 2(b) is a schematic diagram of an existing underground continuous wall as a main supporting member;

FIG. 3 is a schematic diagram of an underground structure system according to one or more embodiments in the present disclosure;

FIG. 4 is a design block diagram of an underground structure system according to one or more embodiments in the present disclosure; and

FIG. 5 is a construction flow chart according to one or more embodiments in the present disclosure.

Reference signs: 1, natural soil; 2, supporting pile; 3, basement exterior wall; 4, backfilled soil; 5, underground continuous wall; 6, frame column; 7, partition wall; and 8, connecting member.

DETAILED DESCRIPTION OF THE EMBODIMENTS Embodiment I

The embodiment provides a structural engineering dominated geotechnical structured permanent supporting system. As shown in FIG. 3 , the structural engineering dominated geotechnical structured permanent supporting system comprises a supporting structure, a main structure, partition walls 7 and backfilled soil 4. In order to combine the supporting structure and the functionally repeated or similar in the main structure, the partition wall 7 replaces the basement exterior wall 3, and the partition wall 7 only blocks the backfilled soil and bears the soil pressure. The basement exterior wall is omitted to form the permanent supporting system only using the supporting structure to bear the soil pressure in the horizontal direction.

As shown in FIG. 2(a) and FIG. 2(b), the horizontal force received by the structural system in the prior art during construction and use is actually the soil pressure applied by natural soil 1. In the supporting structure, the soil pressure in the horizontal direction is borne by supporting piles 2 (underground continuous walls 5). In the main structure, the soil pressure in the horizontal direction is borne by the basement exterior wall 3. The supporting piles 2 (underground continuous walls 5) generally take effect in the construction stage. However, after the construction of the basement exterior wall 3 is completed, the supporting piles 2 (underground continuous walls 5) do not take effect, and the soil pressure in the horizontal direction is borne by the basement exterior wall 3.

Although the existing permanent support can enable the supporting structure to take effect permanently, there are still two types of members in the structural system which have the same function and can independently bear the soil load, namely, the supporting piles 2 (the underground continuous walls 5) and the basement exterior wall 3. The same load is provided with corresponding stressed members in the structures of the two parts, and the members of the two parts can independently bear all the loads. This is because the influence of other parts of the structure in the design is not considered in the structural engineering and the geotechnical engineering, and the interaction between the parts is not considered either, resulting in uneconomical and practical design results.

Through the supporting structure in the embodiment, the partial coefficient of the load is adjusted from 1.25 to 1.35. The influence of the combined action of the main body structure and the supporting structure in later period is considered at the beginning of the design. The supporting structure is designed in the geotechnical engineering, and the common temporary supporting structure is designed into a permanent supporting structure and can bear the soil pressure of the foundation pit permanently.

Further, the supporting structure comprises the supporting piles 2 or the underground continuous walls. When the supporting piles 2 are used as the supporting structure, as shown in FIG. 3 , the supporting piles 2 and the frame columns 6 of the main structure are connected through a plurality of connecting members 8 which are arranged at intervals and parallel to each other.

The partition wall 7 is arranged between every two adjacent frame columns 6. When the supporting piles 2 are designed, the partial coefficient of the load is adjusted from 1.25 to 1.35, and the materials such as concrete and reinforcing steel bars with the strength the same as or higher than that of the main structure are used for construction of the supporting piles 2 in cooperation with the members such as anchor rods. The original temporary support is promoted to be the supporting structure with a permanent function, and the functions of the common supporting structure and the basement exterior wall are combined into one.

The changed supporting piles 2 replace the basement exterior wall 3. In the design, the partition wall 7 satisfying the structural requirements is arranged at the position of the original basement exterior wall 3, and only blocks the backfilled soil and bears the soil pressure. At the same time, the connecting members 8 are designed, and the connecting members 8 are connected to the supporting piles 2 after the main structure construction is completed, so that the combined action is achieved.

Further, the supporting pile 2 is driven into the natural soil 1, and backfilled soil 4 (groove backfill) is filled between the supporting pile 2 and the partition wall 7. After the main structure and the supporting structure are connected, the structures of the two parts become a whole body. When the whole underground structure is constructed and the soil mass is backfilled, the main structure and the supporting structure achieve a combined action; the supporting structure on the outer side and the main structure on the inner side are connected into one body through the connecting members 8, and the interior is filled with rammed backfilled soil 4 to form a composite “pile-soil-wall” structure. The “pile-soil-wall” structure bears all the soil pressure, and can be regarded as a composite exterior wall composed of the supporting structure, the backfilled soil 4 and the main structure together. The composite exterior wall permanently takes effect as a part of the whole structural system.

Embodiment II

The embodiment provides a design method of the structural engineering dominated geotechnical structured permanent supporting system. When the supporting structure comprises the underground continuous walls, as shown in FIG. 5 , the design method comprises the following steps:

Firstly, designing the underground continuous walls according to the partial coefficient of the permanent load in advance; designing the main structure without a basement exterior wall, and designing the connecting members.

Considering the complexity of the geotechnical engineering and the existing design method (permanent supporting design method), a structural engineering dominated scheme in cooperation with the geotechnical engineering is selected. The partial coefficient of the load is changed in the geotechnical engineering. The basement exterior wall is canceled in the structural engineering, and the connecting members are designed, so that active connection is achieved. In the division of work, the work of the structural engineering is more than that of the geotechnical engineering, and the changes made are greater, so the structural engineering is dominated.

The structural engineering is dominated, and the combined action of the main structure and the supporting structure is considered actively. The supporting structure is used as a part of the system in the process of designing the main structure, and the suitable connecting members are designed to achieve the action, so that the purpose of saving manpower and material resources is achieved. Geotechnical engineers need to carry out the design in cooperation with the structural engineering according to the permanent supporting structure, but do not need to make excessive adjustment and design.

Specifically, as shown in FIG. 4 , in order to combine the supporting structure and the functionally repeated or similar members in the main structure, only underground continuous walls, but not the basement exterior wall, are reserved. During the design of the underground continuous walls (the geotechnical design), the partial coefficient of the load is adjusted from 1.25 to 1.35, and the materials such as concrete and reinforcing steel bars with the strength the same as or higher than that of the main structure are used for construction of the supporting piles in cooperation with the members such as anchor rods. The original temporary support is promoted to be the supporting structure with a permanent function, and the functions of the common underground continuous walls and the basement exterior wall are combined into one.

Secondly, after site formation, constructing the supporting structure.

Due to the design of the underground continuous walls according to the permanent supporting structure, the underground continuous walls can be used as a permanent supporting structure to bear the horizontal force applied by foundation pit soil mass on the underground structural system after the construction is completed.

Thirdly, excavating the soil mass in a foundation pit and treating a substrate, and after the treatment, constructing each frame column, connecting beam and floor of the main structure according to the design; After the main structure is completed, the main structure and the underground continuous walls are connected through the connecting members (such as overhanging supports), and after the connection is completed, the supporting structure and the main structure form an integral body so as to achieve the combined action.

Fourthly, constructing a partition wall on the inner side of the groove, wherein the partition wall can be constructed with concrete blocks or other materials, and the partition wall only bears part of the soil pressure of the backfilled soil and plays a blocking role. Therefore, all the underground structures have been constructed, and each member has enough space to meet the requirements of waterproof treatment and later decoration and decoration, and waterproof and antiseptic treatment is performed on the inner side of the underground continuous wall, the outer side of the structural wall and the connecting member.

Firstly, backfilling the soil mass in the groove. The backfilled soil must be tamped in layers. After the soil mass is completely backfilled, the backfilled soil generates a horizontal force on the underground continuous walls on the two sides and the main structure so as to achieve an embedding action of the soil mass on the underground structure. At the moment, the underground continuous walls, the connecting members and the main structure form a complete combined action. The backfilled soil, the supporting structure and the main structure form a whole body. The horizontal force of the external soil on the whole structure is firstly applied to the underground continuous walls. The underground continuous walls are transmitted to the main structure through the connecting members and the backfilled soil. The whole underground structure system achieves a combined action.

As shown in FIG. 1 , in the design process in the prior art, the main structure is designed in the structural engineering, and the supporting structure is designed in the geotechnical engineering. The main structure and the supporting structure are two independent parts in the design, but have a close relation in actual use. The separation of the main structure and the supporting structure in the design results in repeated functions and unnecessary members in the structures of the two parts.

According to the embodiment, the influence of the combined action of the main body structure and the supporting structure in later period is considered at the beginning of the design. The supporting structure is designed in the geotechnical engineering, and the common temporary supporting structure is designed into a permanent supporting structure and can bear the soil pressure of the foundation pit permanently. The basement exterior wall is no longer designed in the structural engineering. Only a partition wall meeting the structural requirements is designed to withstand the soil pressure of the backfilled soil, and the design of the connecting members is added. All the designs are based on the premise that the main structure and the supporting structure achieve the combined action through the connecting members.

The foregoing descriptions are merely exemplary embodiments of the present disclosure, but are not intended to limit the present disclosure, and for the skill in the art, the present disclosure can be of various modifications and changes. Any modification, equivalent replacement, or improvement made without departing from the spirit and principle of this application shall fall within the protection scope of this application. 

1. A structural engineering dominated geotechnical structured permanent supporting system, comprising a supporting structure designed on the basis of the partial coefficient of a permanent load, wherein the supporting structure is connected to frame columns of a main structure through a plurality of connecting members arranged at intervals, and a partition wall for blocking soil mass is arranged between every two adjacent frame columns to form a permanent supporting system only bearing soil pressure in the horizontal direction of the supporting structure.
 2. The structural engineering dominated geotechnical structured permanent supporting system according to claim 1, wherein backfilled soil is filled between the partition wall and the supporting structure.
 3. The structural engineering dominated geotechnical structured permanent supporting system according to claim 1, wherein the material strength of the supporting structure is the same as or higher than that of the main structure.
 4. The structural engineering dominated geotechnical structured permanent supporting system according to claim 1, wherein the backfilled soil is rammed backfilled soil, and the side, away from the backfilled soil, of the supporting structure is natural soil.
 5. A design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 1, comprising the following steps: designing the supporting structure according to the partial coefficient of the permanent load in advance; designing the main structure without a basement exterior wall, and designing the connecting members; constructing the supporting structure, excavating the soil inside a foundation pit and treating a substrate; constructing the main structure, and connecting the main structure with the supporting structure through the connecting members; and constructing the partition walls in grooves, and then backfilling soil mass in the grooves.
 6. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 5, wherein when the supporting structure is designed, considering the influence of the combined action of the main structure and the supporting structure in later period, the main structure can bear the soil pressure permanently.
 7. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 6, wherein based on the design of the main structure, the supporting structure is designed in cooperation with the main structure.
 8. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 5, wherein the inner side of the supporting structure, the outer side of the partition wall and the connecting member are all subjected to waterproof and antiseptic treatment.
 9. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 5, wherein after the soil mass in the grooves is backfilled, the backfilled soil is compacted in layers.
 10. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 5, wherein the supporting members of the supporting structure are supporting piles or underground continuous walls.
 11. The structural engineering dominated geotechnical structured permanent supporting system according to claim 2, wherein the material strength of the supporting structure is the same as or higher than that of the main structure.
 12. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 4, wherein backfilled soil is filled between the partition wall and the supporting structure.
 13. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 4, wherein the material strength of the supporting structure is the same as or higher than that of the main structure.
 14. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 5, wherein the material strength of the supporting structure is the same as or higher than that of the main structure.
 15. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 4, wherein the backfilled soil is rammed backfilled soil, and the side, away from the backfilled soil, of the supporting structure is natural soil.
 16. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 12, wherein when the supporting structure is designed, considering the influence of the combined action of the main structure and the supporting structure in later period, the main structure can bear the soil pressure permanently.
 17. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 13, wherein when the supporting structure is designed, considering the influence of the combined action of the main structure and the supporting structure in later period, the main structure can bear the soil pressure permanently.
 18. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 14, wherein when the supporting structure is designed, considering the influence of the combined action of the main structure and the supporting structure in later period, the main structure can bear the soil pressure permanently.
 19. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 15, wherein when the supporting structure is designed, considering the influence of the combined action of the main structure and the supporting structure in later period, the main structure can bear the soil pressure permanently.
 20. The design method of the structural engineering dominated geotechnical structured permanent supporting system according to claim 16, wherein based on the design of the main structure, the supporting structure is designed in cooperation with the main structure. 